Tips and Tricks to Simplify Multiarterial CABG
Dr Om P. Yadava, CEO and Chief Cardiac Surgeon of the National Heart Institute in New Delhi, India, and Editor-in-Chief of the Indian Journal of Thoracic and Cardiovascular Surgery, and Mr Clifford Barlow, Senior Consultant Cardiac Surgeon at the University Hospital in Southampton, UK, discuss ways to increase the uptake of multiarterial grafting in CABG through simplification rather than complex configurations.
Dr Yadava laments that despite the literature available, total arterial grafting is not catching up, with less than 5% of coronary artery bypass graft surgery worldwide being multiarterial grafting. Dr Clifford also feels that there is sufficient evidence, implicit or explicit, for the benefit of bilateral internal mammary arteries (IMA), but there has not been sufficient uptake. Exploring reasons for this, Dr Barlow quotes Einstein, “We keep proposing doing the same thing over and over again, expecting a different result.” The main reason for this low uptake, he feels, is the technical complexity of the operation. Dr Clifford proposes a simplified concept – pedicled LIMA to left anterior descending (LAD) and pedicled RIMA through the transverse sinus, behind the aorta, to the circumflex/obtuse marginal (OM) branch. However, if the OM branch is too far off for the RIMA to reach, then a free RIMA can be used, but the top end should not be performed to the aorta (1). Dr Clifford opposes a pedicled RIMA to the right coronary artery (RCA) because the tension on the graft is difficult to predict, especially if there happens to be cardiac dilatation or distention due to a temporary arrhythmia or ischemia in the postoperative phase. To the contrary, a graft via the transverse sinus is not affected by the postoperative distention of the heart. Though bleeding point may be an issue with such a dispensation of the graft, it is easily surmountable.
Dr Yadava proposes taking a pedicled RIMA across the midline to the LAD and a pedicled LIMA to the back of the heart, but Dr Clifford feels redo may be a difficult proposition in this scenario, more so if a patient has to come back for a mitral or aortic valve intervention. Dr Clifford expresses his dislike for composite "T" grafting, because he believes that this is somewhat anti-anatomical. He feels that there are not many instances in the human body where a small artery arises at a right angle from another small artery, though these may arise from big arteries, like the aorta. Even the flow dynamics of the "T" graft and the consequent turbulence is not physiological. He is also concerned for the degree of relative flow in the two limbs of the "T" graft. He seems to accept that an acute angle with the use of "Y" grafting may be a valid technique. However, even here, the potential steal can occur if the degree of stenosis is unbalanced in the two arms. Dr Clifford is strongly in favor of simplifying grafting techniques and configurations to increase the uptake of multiarterial grafting.
Barlow CW. What is the best second conduit for coronary artery bypass grafting? With no silver bullet study we should not ignore good regular bullets when we get them! J Thorac Cardiovasc Surg. 2015;150(6):1535-1536.